Screening the community for Alzheimer's disease (AD) will become an increasingly important public health priority as new and more effective treatments for AD continue to emerge. Screening for preclinical AD is a research priority, a necessary step towards understanding the early course of the disease and conducting secondary prevention studies designed to delay or prevent the onset of clinically diagnosable disease. This project emphasizes the validation of telephone-based screening tools for early AD and preclinical AD in the context of a longitudinal population-based study. We propose to administer our novel telephone screening battery and the best currently available alternative (the Telephone Instrument for Cognitive Status: TICS, a telephone version of the Mini-Mental State Exam) to a population-based sample recruited from the Health Care Financing Administration (HCFA) lists. Subjects will receive the telephone battery 3 times at 18 month intervals. Full clinical assessments will follow to determine dementia status at cross-section and over time. We will examine the cross-sectional and predictive validity of our telephone battery. Although this project tests methods for telephone screening, success in this area will provide a foundation for screening using other modes of administration, including face-to-face interviews. The tools we develop have promise for immediate research applications and for future public health interventions.